All information on this page courtesy of: http://www.gigabyte.us/Products/Motherboard/Products_Spec.aspx?ClassValue=Motherboard&ProductID=3250&ProductName=GA-P55A-UD4P and http://www.gigabyte.us/Products/Motherboard/Products_Spec.aspx?ClassValue=Motherboard&ProductID=3242&ProductName=GA-P55A-UD6